Processes in Software Development. Presented by Lars Yde, M.Sc., at Selected Topics in Software Development, DIKU spring semester 2008

Transcription

1 Processes in Software Development Presented by Lars Yde, M.Sc., at Selected Topics in Software Development, DIKU spring semester 2008

2 Software hall of shame

3 Classic mistakes

4 ACM Code of Ethics As an ACM member I will Contribute to society and human well-being. Avoid harm to others. Be honest and trustworthy. Be fair and take action not to discriminate. Honor property rights including copyrights and patent. Give proper credit for intellectual property. Respect the privacy of others. Honor confidentiality.

5 Catastrophic bugs July 28, Mariner I space probe Soviet gas pipeline Therac-25 medical accelerator Buffer overflow in Berkeley Unix finger daemon Kerberos Random Number Generator. January 15, AT&T Network Outage Intel Pentium floating point divide. 1995/ The Ping of Death. June 4, Ariane 5 Flight 501. November National Cancer Institute, Panama City.

6 What users do, not what they say Source: steampowered.com

7 The 10th edition of the annual CHAOS report from The Standish Group The 2004 CHAOS report, entitled CHAOS Chronicles, found total U.S. project waste to be $55 billion, made up of $38 billion in lost dollar value and $17 billion in cost overruns. Total project spending was found to be $255 billion in the 2004 report. In 1994, The Standish Group estimated U.S. IT projects wasted $140 billion $80 billion of that from failed projects out of a total of $250 billion in project spending. Standish Chairman Jim Johnson says, The primary reason is the projects have gotten a lot smaller. Doing projects with iterative processing as opposed to the waterfall method, which called for all project requirements to be defined up front, is a major step forward. Softwaremag.com, January Issue 2004

8 Brief history of software dev meth

9 Scripted methodology / framework Waterfall / Big Design Up Front (BDUF) Spiral Unified Process Microsoft Solutions Framework CMM / CMMI ITIL Six Sigma Et al

10 The virtuous cycle that never was Source: notetech.com

11 Scripted methodology #2: spiral Boehm, Barry: A Spiral Model of Software Development and Enhancement, 1988

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13 Scripted methodology #1 : waterfall

14 Rational Unified Process Adapt the process Develop a Vision Balance stakeholder priorities Manage to the Plan Collaborate across teams Identify and Mitigate Risks Demonstrate value iteratively Assign and Track Issues Elevate the level of abstraction Examine the Business Case Focus continuously on quality Design a Component Architecture Incrementally Build and Test the Product Verify and Evaluate Results Manage and Control Changes Provide User Support

15 CMM / CMMI

16 Agile Manifesto Our highest priority is to satisfy the customer through early and continuous delivery of valuable software. Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage. Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale. Business people and developers must work together daily throughout the project. Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done. The most efficient and effective method of conveying information to and within a development team is face-to-face conversation. Working software is the primary measure of progress. Agile processes promote sustainable development. The sponsors, developers, and users should be able to maintain a constant pace indefinitely. Continuous attention to technical excellence and good design enhances agility. Simplicity--the art of maximizing the amount of work not done--is essential. The best architectures, requirements, and designs emerge from self-organizing teams. At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly.

17 Agile practices Scrum (sprints, product owners, daily scrumming, deliverables, retrospective) XP (pair programming,refactoring, simplicity, courage) Crystal (people focus) DSDM (pareto principle, MoSCoW, goodenough delivery) Lean

18 Lean software development Eliminate waste (redundancies, duplicate code, lack of clarity, etc) identify through eg. code review, remedy through eg. generic programming / refactoring / mercilessness Amplify learning (small iterations, 1:1's, customer interaction) Decide as late as possible (small increments, RAD, thoughtful design, loosely coupled code) Deliver as fast as possible (clear goals, achievable goals, high velocity, daily scrumming, removing churn/context switching) Empower the team (trust, high-level instruction) Build integrity in (transparency, loyalty to the vision, clear focus) See the whole (system in context)

19 Deming's deadly diseases Lack of constancy of purpose. Emphasis on short-term profits. Evaluation by performance, merit rating, or annual review of performance. Mobility of management. Running a company on visible figures alone. Excessive medical costs. Excessive costs of warranty, fueled by lawyers who work for contingency fees.

20 Six Sigma

21 Cost of correction relative to phase

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